Insulator.



No. 633,!76. Patented Sept. l9, I899.

F. H. WITHYCOIBE.

| N S U LA T0 R.

(Application filed Fab. 2;, 1899.)

(No Model.)

UNITED STATES PATENT Curios.

FREDERICK HENRY WITIIYCOMBE, OF MON"REAL, lANADA, ASSIGNOR Ol ELEVEN-TWENTIETHS TO CLEMILN" HENRY MULEOD, Oh SAME PLACE.

INSULArOR.

SPECIFICATION forming part of Letters Patent No. 633,1? 6, dated September 19, 1899.

Application filed February 2,1899. berial No. 704,819. (No model.)

To (Ii/Z when it may calmer-71,;

Be it known that I, FREDERICK HENRY \VITHYOOMBE, of the city of Montreal, Province of Quebec, Canada, have invented certain new and useful Improvements in Insulators; and I do hereby declare that the following is a full, clear, and exact description of the same.

It is well known that the glass and other lo insulators used on telegraph and other electric lines are frequently made the targets of and are damaged by stones and other missiles. The damage resulting partially or wholly destroys their usefulness and necessitates the trouble and expense of replacing them, besides causing inconvenience by the interruption of communication or by breakage.

My invention relates to the special construction of the exposed surfaces of the insulators 2o apart from the general design or material employed.

My invention has for its object to render insulators less liable to breakage by providing a simple and efficient means to enable them the better to withstand the impact of foreign bodies.

The invention consists generally in replacing the smooth outer surfaces of insulators as now made of glass, porcelain, or other in- 0 sulating material by an outer surface construction of small protuberances, ridges, or depressions, each protuberance or ridge being of greater height than thickness. These small protuberances, ridges, or intervening 3 5 portions between the depressions, which may be of any desired section, form an exterior construction which will break down readily with the impact of missiles. This breaking down of the intercepting parts cushions the to blow and relieves the main portion or body of the insulator or extension therefrom from the full severity of the impact. It will thus be seen that the small parts with whichthe mis sile first comes into contact, offering a sufficiently less resistance than that portion of the main body or extension therefrom itis intended to protect, will crush or crumble under the force of impact, and thus cushion the blow by using up a large proportion of the energy. Experiment has proved this to be the case.

Insulators having a number of petticoats, whether extending horizontally, vertically, or obliquely, of proportions which render them very easy of breakage by missiles can thus be made to offer greater resistance to fracture by forming the exposed surfaces in the way and as herein described.

Reference is made to the annexed drawing, which is an elevation,half in section,illustrat- 6o ing one application of the invention to one form of insulator.

The insulator shown is of the same general form as those now in use, having a central cylindrical part 1, surmounted by a domeshaped upper portion orcrown 2, and having depending from it the petticoat The interior is provided with the usual threads at, adapted to screw on the end of the supporting pin, peg, or stick. The usual groove 5 is provided for attaching the wire.

The insulator shown in the drawing is formed with small depressions (3, which may be of any desired shape (conoidal, triangular, orpyramidal, as shown, orotherwise) and preferably arranged in oblique cross-hatch lines, as shown, or in any other desired manner, so that there can be no interference with the flow of water, the portion 7 intervening between the depressions being in every case preferably of greater height than thickness and forming a protective cushion on the exposed surfaces of the insulator and extensions therefrom. The function of such a surface formation (made up, as it is, of a numher of small depressions and theintervening portions, which may be of any desired section) is that when a missile strikes the insulator it will come in contact first with the portions intervening between the depressions 0 in such surfaces,which, being of a fragile or easily-broken and yielding formation, will give way to the impact of the foreign body. Thus in the form shown theintervening portions would be first broken down. The en- 5 ergy of the impact will be largely expended in crushing these parts. The result will be to cushion the blow and reduce its severity 2. An insulator the surface of which is divided up into small depressions 0 and inter- Vening portions '7 arranged in oblique cross hate-l1 lines and the rib portions adapted to form a protective cushion, for the purpose set forth.

In testimony whereof I have affixed my signature in presence of two witnesses.

FREDERICK HENRY \VI'IIIYOOMIXI'L \Vitnesses:

FRED. J. SEARS, LoRNE A. MACKENZIE. 

